import React, { useRef } from 'react'
import store from '../../store'

function Count() {
  const selectNumberRef = useRef()

  // 加
  const increment = () => {
    const { value } = selectNumberRef.current
    store.dispatch({
      type: 'increment',
      data: +value
    })
  }

  // 减
  const decrement = () => {
    const { value } = selectNumberRef.current
    store.dispatch({
      type: 'decrement',
      data: +value
    })
  }

  // 如果为奇数，则加
  const incrementIfOdd = () => {
    const { value } = selectNumberRef.current
    const count = store.getState()
    if (count % 2 !== 0) {
      store.dispatch({
        type: 'increment',
        data: +value
      })
    }
  }

  // 异步延迟加
  const incrementIfAsync = () => {
    const { value } = selectNumberRef.current
    setTimeout(() => {
      store.dispatch({
        type: 'increment',
        data: +value
      })
    }, 500)
  }

  return (
    <div style={{ width: 500, margin: '0 auto' }}>
      <h1>当前求和为：{store.getState()}</h1>
      <select ref={selectNumberRef}>
        <option value='1'>1</option>
        <option value='2'>2</option>
        <option value='3'>3</option>
      </select>
      <button onClick={increment}>+</button>
      <button onClick={decrement}>-</button>
      <button onClick={incrementIfOdd}>当前求和为奇数再加</button>
      <button onClick={incrementIfAsync}>异步加</button>
    </div>
  )
}

export default Count
